1. Field of the Invention
The invention relates to an electrode having at least two partial electrode elements, in particular a neutral electrode for HF-surgery (i.e., High-Freguency electrosurgery), in which the partial electrodes are arranged in juxtaposition in a pre-established direction.
2. Description of the Prior Art
A neutral electrode of the above-mentioned type operates with two flat electrodes, as described in German Registered Design Patent GM No. 82 05 363, In this neutral electrode the electrical contact with the patient is monitored by means of a control circuit through which a low frequency control current flows. This control current flows from the contact surface of one partial electrode, through the skin of the patient, to the contact surface of the other partial electrode.
Another two element neutral electrode is described in German Patent Publication DE-OS No. 28 49 422.
Single element neutral electrodes are also employed in the present state of the art. HF-surgical apparatuses are frequently equipped with a monitoring circuit through which a check may be made to determine whether the single element electrode is in fact present in the circuit, i.e. is connected. For this purpose, a first and a second connecting lead is attached to the surface of the single element electrode. A control current is sent from the first connecting lead through the neutral electrode and the second connecting lead. If this control current exceeds a pre-established threshold, assurance is gained that the single element electrode is in fact present and does not have a defective electrical connection and/or has not become disconnected. The construction of the neutral electrode proposed herein is, in particular, to be capable of working in combination with a monitoring circuit of this type.
lt has been demonstrated that a multi-element construction of the neutral electrode is also desirable, when an indication is to be provided by a monitoring circuit of whether such a neutral electrode makes large surface area contact or just a spot contact with the patient during the surgical procedure. Such a monitoring circuit is described in U.S. patent application Ser. No. 929,561, filed Nov. 10, 1986 and titled "Method and Apparatus for Monitoring the Surface Contact of a Neutral Electrode of an HF-Surgical Apparatus".
In the construction of a neutral electrode, every effort must be made to design it in such a way that good surface contact with the patient is assured. In the case of two element electrodes (i.e., two partial electrodes), this has previously resulted in a rectangular shape. If the two partial electrodes are arranged in juxtaposition in a pre-established direction, and if the connecting cable conductor is led to the electrode in this pre-established direction, a condition results where the conductor or lead for one of the partial electrodes must be longer than that for the other of the partial electrodes. This requires particular care in the fabrication of the neutral electrode in order that no interchange of the conducting leads can occur. Moreover, conductors of different length must be kept on hand.
An object of the present invention is to construct a multi-element electrode that will allow for simpler fabrication. In particular, assurance is to be provided that conductors of equal length may be connected to the partial electrodes.